Nasa's InSight mission will target 'Marsquakes'

"The American space agency launches its latest mission to Mars this weekend."

Blimey, they seem to launch one every week (if anyone believes it, and if they do they'll believe anything ). But 'Marsquakes'? What a clever play on words? Same as Earthquakes, but on Mars . . . geddit? It took me three days to reali . . .